应兰州大学数学与统计学院王智诚教授和张亮副教授的邀请，华南师范大学丁维维副研究员将于2021年4月27日-4月28日与我校有关师生进行在线学术研讨，其中4月27日举行线上专题学术报告。

报告题目:Admissible speeds in spatially periodic bistable reaction-diffusion equations

报告摘要：Spatially periodic reaction-diffusion equations typically admit pulsating waves whichdescribe the transition from one steady state to another. Due to the heterogeneity, ingeneral such an equation is not invariant by rotation and therefore the speed of thepulsating wave may a priori depend on its direction. However, little is actually knownin the literature about whether it truly does: surprisingly, it is even known in theone-dimensional monostable Fisher-KPP case that the speed is the same in the opposite directions despite the lack of symmetry. In this talk,we will discuss this issue in thebistable case and show that the set of admissible speeds is actually rather large, whichmeans that the shape of propagation may indeed be asymmetrical. More precisely, weshow in any spatial dimension that one can choose an arbitrary large number of directions, and find a spatially periodic bistable type equation to achieve any combinationof speeds in those directions, provided those speeds have the same sign. In particular,in spatial dimension 1 and unlike the Fisher-KPP case, any pair of (either nonnegativeor nonpositive) rightward and leftward wave speeds is admissible.

时 间：4月27日下午16:00.

地 点：腾讯会议ID：219 169 763

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丁维维副研究员简介

丁维维，华南师范大学副研究员，2015年3月博士毕业于中国科学技术大学和法国艾克斯-马赛大学，2015年4月至2019年5月在澳大利亚新英格兰大学、日本东京大学、日本明治大学从事博士后研究。主要研究领域为非线性抛物型方程的动力学性质，及其在生物问题上的应用。在JMPA、AIHP Analyse Non Lineaire、SIMA、CVPDE、JDE等杂志上发表论文十余篇。已主持完成日本Grant-in-Aid for JSPS Fellows （17F17021）一项，正主持国家自然科学基金青年项目一项、广东省基础与应用基础研究青年基金一项。

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